1. Field of the Invention
This invention relates to retractors, and more particularly to an access platform that facilitates access to the interior of the chest cavity during surgical procedures.
2. Background of the Invention
Diseases of the cardiovascular system affect millions of people each year and are a leading cause of death in the United States and throughout the world. The cost to society from such diseases is enormous both in terms of lives lost and the cost of treating cardiac disease patients through surgery. A particularly prevalent form of cardiovascular disease is a reduction in the blood supply to the heart caused by atherosclerosis or other conditions that create a restriction in blood flow at a critical point in the cardiovascular system leading to the heart. In many cases, a blockage or restriction in the blood flow leading to the heart can be treated by a surgical procedure known as a Coronary Artery Bypass Graft (CABG) procedure, which is more commonly known as a xe2x80x9cheart bypassxe2x80x9d operation. In the CABG procedure, the surgeon either removes a portion of a vein from another part of the body to use as a graft and installs the graft at points that bypass the obstruction to restore normal blood flow to the heart or detaches one end of an artery and connects that end past the obstruction while leaving the other end attached to the arterial supply to restore normal blood flow to the heart.
Although the CABG procedure has become relatively common, i.e., heart bypass surgery is performed in one of every thousand persons in the United States, the procedure is lengthy and traumatic and can damage the heart, the central nervous system, and the blood supply. In a conventional CABG procedure, the surgeon cuts off the blood flow to the heart and then stops the heart from beating in order to install the graft. Thus, in order to perform the conventional CABG procedure, the surgeon must make a long incision down the middle of the chest, saw through the entire length of the sternum, spread the two halves of the sternum apart, and then perform several procedures necessary to attach the patient to a cardiopulmonary bypass machine to continue the circulation of oxygenated blood to the rest of the body while the graft is sewn in place.
The CABG procedure further requires that a connection for the flow of blood be established between two points that xe2x80x9cby passxe2x80x9d a diseased area and restore an adequate blood flow. Typically, one end of a graft is sewn to the aorta, while the other end of the graft is sewn to a coronary artery, such as the left anterior descending (LAD) artery that provides blood flow to the main muscles of the heart. This procedure is known as a xe2x80x9cfree bypass graft.xe2x80x9d Alternatively, the IMA pedicle is dissected off of the chest wall, while still attached to its arterial supply, and attached to the LAD past the obstruction. This procedure is known as an xe2x80x9cin situ bypass graft.xe2x80x9d
In an in situ bypass graft, the IMA must be dissected from its connective tissue until there is sufficient slack in the IMA to insure that the graft does not kink after it is installed. The IMAs, left and right, extend from the subclavian arteries in the neck to the diaphragm and run along the backside of the rib cage adjacent the sternum. During a conventional in situ bypass graft, typically the left half of the sternum is raised to increase the surgeon""s access to the left IMA (LIMA) and the heart. A device used for this type of sternal retraction is disclosed in United Kingdom Patent Application No. GB 2267827 A, xe2x80x9cA device for Internal Mammary artery dissection.xe2x80x9d
Although several efforts have been made to make the CABG procedure less invasive and less traumatic, most techniques still require cardiac bypass and cardioplegia (stoppage of the heart). The safety and efficacy of CABG procedure could be improved if the surgeon could avoid the need to stop the heart from beating during the procedure, thereby eliminating the need to connect the patient to a cardiopulmonary bypass machine to sustain the patient""s life during the CABG procedure and, thus, eliminate the need for the lengthy and traumatic surgical procedures necessary to connect the patient to a cardiopulmonary bypass machine. In recent years, a small number of surgeons have begun performing CABG procedures using surgical techniques especially developed to enable surgeons to perform the CABG procedure while the heart is still beating. In such procedures, there is no need for any form of cardiopulmonary bypass, no need to perform the extensive surgical procedures necessary to connect the patient to a cardiopulmonary bypass machine, cardioplegia is rendered unnecessary, the surgery is much less invasive and traumatic, and the entire procedure can typically be achieved through one or two comparatively small incisions (thoracotomies) in the chest.
Despite these advantages, the beating-heart CABG procedure is not widely practiced, in part, because of the difficulty in performing the necessary surgical procedures with conventional instruments while the heart is still beating. If specially designed instruments were available so that the CABG procedure could more easily be performed on the beating heart, the beating-heart CABG procedure would be more widely practiced and the treatment of cardiovascular disease would be improved in a significant part of the cardiovascular disease patient population.
Since the xe2x80x9cbeating-heartxe2x80x9d CABG procedure is performed while the heart muscle is continuing to beat or contract, an anastomosis is difficult to perform because the blood continues to flow and the heart continues to move while the surgeon is attempting to sew the graft in place. The surgical procedure necessary to install the graft requires placing a series of sutures through several extremely small vessels that continue to move during the procedure. The sutures must become fully placed so that the graft is firmly in place and does not leak. It is also important that the procedure be performed rapidly because the blood flow through the artery may be interrupted or reduced during the procedure to allow the graft to be installed. This can cause ischemia, which should be minimized. Also, the surgeon""s working space and visual access are limited because the surgeon may be working through a small incision in the chest or may be viewing the procedure on a video monitor, such that the site of the surgery is viewed via a surgical scope.
The xe2x80x9cbeating-heartxe2x80x9d CABG procedure could be greatly improved if the surgeon""s working space and visual access to the heart and the IMA were increased and improved. Current methods to increase and improve the surgeon""s working space and visual access include laterally spreading or retracting the ribs with a conventional rib spreader/retractor, and then vertically displacing one of the retracted ribs relative to the other retracted rib to create a xe2x80x9ctunnelxe2x80x9d under the rib cage. To vertically displace one of the retracted ribs, some force external to the rib spreader must be applied to the rib. Typically, a surgeon""s assistant will push or pull upwardly on the rib with a device having a rib blade inserted under the rib. However, the surgeon""s assistant must then hold the rib in a vertically displaced position for the duration of the IMA dissection, resulting in an undesirable addition of another set of hands around the surgical area.
Another method used by surgeons to vertically displace the retracted rib is to insert a rib blade under the retracted rib and then attach the rib blade to a winch located above the patient. The winch is then operated to pull upwardly on the rib and hold it in a vertically displaced position. However, it is not at all uncommon for the patient to be raised off the operating table by the winch. This is undesirable because if the rib begins to crack or break, the weight of the patient""s body will cause the rib to continue to break until the patient reaches the operating table.
While using these methods to vertically displace one of the retracted ribs, it may be desirable to further increase a surgeon""s working space and visual access by depressing the sternum or the other retracted rib. However, depression of the sternum or the other retracted rib undesirably adds further sets of hands around the surgical site.
Furthermore, these methods and devices tend to limit where the thoracotomy can be performed. For example, if the thoracotomy is performed on the lateral side of the chest, the conventional rib spreader would tend to xe2x80x9cstand-upxe2x80x9d vertically from the ribs it is retracting such that it would intrude on the surgeon""s working space. In addition, if a winch is used to offset the ribs, the lifting action of the winch will tend to rotate the patient to an undesirable and often unstable position for performing the IMA.
Equally important to improving the xe2x80x9cbeating heartxe2x80x9d CABG procedure, is the ability to retract the soft tissue around the incision in the chest to draw the soft tissue away from the surgeon""s working area. However, none of the methods or devices described above provide the ability to perform soft tissue retraction.
Thus, in view of the shortcomings of these devices and methods for increasing a surgeon""s working space and visual access during a xe2x80x9cbeating-heartxe2x80x9d CABG procedure, it would be desirable to have a device that is capable of laterally spreading the ribs and vertically displacing opposing retracted ribs relative to each other, that is capable of depressing the sternum, that is self-contained such that the force necessary to spread and vertically displace the ribs, and the force necessary to depress the sternum, is applied by the access platform itself rather than through additional external devices, that does not limit the location where a thoracotomy can be performed, and that is capable of soft tissue retraction.
The access platform of the present invention serves to facilitate the dissection of an internal mammary artery (IMA), including both proximal and distal dissection, and access to the heart during a xe2x80x9cbeating heartxe2x80x9d Coronary Artery Bypass Graft (CABG) procedure by increasing the surgeon""s working space and visual access. The access platform of the present invention is preferably capable of laterally spreading the ribs, vertically displacing the opposingly retracted ribs relative to each other and depressing the sternum to cause a xe2x80x9ctunnelxe2x80x9d effect under the retracted ribs. Moreover, it is preferably self-contained such that the force necessary to spread and vertically displace the ribs is applied by the access platform itself rather than through additional external devices. The access platform preferably comprises first and second blades interconnected to a spreader member that laterally drives the blades apart or together, a sternal pad interconnected to the blades, and a vertical displacement member interconnected to a blade and the spreader member. The vertical displacement member may preferably be bi-directional to cause the interconnected blade to be vertically displaced in either direction and, thus, increases the surgeon""s working space and visual access to the IMA.
In addition, the access platform preferably includes an integrated tissue retractor, a hinged connector interconnected to the blades and the spreader member, and a port interconnected to the blades. The tissue retractor advantageously draws the soft tissue around an incision away from the surgeon""s working area. The port advantageously provides a mount for a heart stabilizer, a scope for IMA take down, an IMA clamp, an IMA holder or other tools necessary for a xe2x80x9cbeating heartxe2x80x9d CABG procedure. The hinged connector advantageously pivots the access platform away from the surgeon""s working area.
In other embodiments, the superior blade is preferably pivotally mounted to the spreader member at a pivot point above the blade. The superior blade is naturally lifted as a spreading force from the inferior blade is transmitted to the superior blade through the pivot. The sternal pad may preferably be rotatably coupled to the superior blades.
In further embodiments, bladeless embodiments comprising tubular or hollow conically shaped bodies provide access to a patient""s chest cavity.
It is an object of the present invention to provide an improved access platform.
Another object of the present invention is to provide an improved tissue retractor.
Further objects and advantages of the present invention will become apparent from a consideration of the drawings and the ensuing description.